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<a name="Packets"></a>
<div class="header">
<p>
Next: <a href="Stop-Reply-Packets.html#Stop-Reply-Packets" accesskey="n" rel="next">Stop Reply Packets</a>, Previous: <a href="Overview.html#Overview" accesskey="p" rel="prev">Overview</a>, Up: <a href="Remote-Protocol.html#Remote-Protocol" accesskey="u" rel="up">Remote Protocol</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html#Concept-Index" title="Index" rel="index">Index</a>]</p>
</div>
<hr>
<a name="Packets-1"></a>
<h3 class="section">E.2 Packets</h3>

<p>The following table provides a complete list of all currently defined
<var>command</var>s and their corresponding response <var>data</var>.
See <a href="File_002dI_002fO-Remote-Protocol-Extension.html#File_002dI_002fO-Remote-Protocol-Extension">File-I/O Remote Protocol Extension</a>, for details about the File
I/O extension of the remote protocol.
</p>
<p>Each packet&rsquo;s description has a template showing the packet&rsquo;s overall
syntax, followed by an explanation of the packet&rsquo;s meaning.  We
include spaces in some of the templates for clarity; these are not
part of the packet&rsquo;s syntax.  No <small>GDB</small> packet uses spaces to
separate its components.  For example, a template like &lsquo;<samp>foo
<var>bar</var> <var>baz</var></samp>&rsquo; describes a packet beginning with the three ASCII
bytes &lsquo;<samp>foo</samp>&rsquo;, followed by a <var>bar</var>, followed directly by a
<var>baz</var>.  <small>GDB</small> does not transmit a space character between the
&lsquo;<samp>foo</samp>&rsquo; and the <var>bar</var>, or between the <var>bar</var> and the
<var>baz</var>.
</p>
<a name="index-thread_002did_002c-in-remote-protocol"></a>
<a name="thread_002did-syntax"></a><p>Several packets and replies include a <var>thread-id</var> field to identify
a thread.  Normally these are positive numbers with a target-specific
interpretation, formatted as big-endian hex strings.  A <var>thread-id</var>
can also be a literal &lsquo;<samp>-1</samp>&rsquo; to indicate all threads, or &lsquo;<samp>0</samp>&rsquo; to
pick any thread.
</p>
<p>In addition, the remote protocol supports a multiprocess feature in
which the <var>thread-id</var> syntax is extended to optionally include both
process and thread ID fields, as &lsquo;<samp>p<var>pid</var>.<var>tid</var></samp>&rsquo;.
The <var>pid</var> (process) and <var>tid</var> (thread) components each have the
format described above: a positive number with target-specific
interpretation formatted as a big-endian hex string, literal &lsquo;<samp>-1</samp>&rsquo;
to indicate all processes or threads (respectively), or &lsquo;<samp>0</samp>&rsquo; to
indicate an arbitrary process or thread.  Specifying just a process, as
&lsquo;<samp>p<var>pid</var></samp>&rsquo;, is equivalent to &lsquo;<samp>p<var>pid</var>.-1</samp>&rsquo;.  It is an
error to specify all processes but a specific thread, such as
&lsquo;<samp>p-1.<var>tid</var></samp>&rsquo;.  Note that the &lsquo;<samp>p</samp>&rsquo; prefix is <em>not</em> used
for those packets and replies explicitly documented to include a process
ID, rather than a <var>thread-id</var>.
</p>
<p>The multiprocess <var>thread-id</var> syntax extensions are only used if both
<small>GDB</small> and the stub report support for the &lsquo;<samp>multiprocess</samp>&rsquo;
feature using &lsquo;<samp>qSupported</samp>&rsquo;.  See <a href="General-Query-Packets.html#multiprocess-extensions">multiprocess extensions</a>, for
more information.
</p>
<p>Note that all packet forms beginning with an upper- or lower-case
letter, other than those described here, are reserved for future use.
</p>
<p>Here are the packet descriptions.
</p>
<dl compact="compact">
<dt>&lsquo;<samp>!</samp>&rsquo;</dt>
<dd><a name="index-_0021-packet"></a>
<a name="extended-mode"></a><p>Enable extended mode.  In extended mode, the remote server is made
persistent.  The &lsquo;<samp>R</samp>&rsquo; packet is used to restart the program being
debugged.
</p>
<p>Reply:
</p><dl compact="compact">
<dt>&lsquo;<samp>OK</samp>&rsquo;</dt>
<dd><p>The remote target both supports and has enabled extended mode.
</p></dd>
</dl>

</dd>
<dt>&lsquo;<samp>?</samp>&rsquo;</dt>
<dd><a name="index-_003f-packet"></a>
<a name="g_t_003f-packet"></a><p>Indicate the reason the target halted.  The reply is the same as for
step and continue.  This packet has a special interpretation when the
target is in non-stop mode; see <a href="Remote-Non_002dStop.html#Remote-Non_002dStop">Remote Non-Stop</a>.
</p>
<p>Reply:
See <a href="Stop-Reply-Packets.html#Stop-Reply-Packets">Stop Reply Packets</a>, for the reply specifications.
</p>
</dd>
<dt>&lsquo;<samp>A <var>arglen</var>,<var>argnum</var>,<var>arg</var>,&hellip;</samp>&rsquo;</dt>
<dd><a name="index-A-packet"></a>
<p>Initialized <code>argv[]</code> array passed into program. <var>arglen</var>
specifies the number of bytes in the hex encoded byte stream
<var>arg</var>.  See <code>gdbserver</code> for more details.
</p>
<p>Reply:
</p><dl compact="compact">
<dt>&lsquo;<samp>OK</samp>&rsquo;</dt>
<dd><p>The arguments were set.
</p></dd>
<dt>&lsquo;<samp>E <var>NN</var></samp>&rsquo;</dt>
<dd><p>An error occurred.
</p></dd>
</dl>

</dd>
<dt>&lsquo;<samp>b <var>baud</var></samp>&rsquo;</dt>
<dd><a name="index-b-packet"></a>
<p>(Don&rsquo;t use this packet; its behavior is not well-defined.)
Change the serial line speed to <var>baud</var>.
</p>
<p>JTC: <em>When does the transport layer state change?  When it&rsquo;s
received, or after the ACK is transmitted.  In either case, there are
problems if the command or the acknowledgment packet is dropped.</em>
</p>
<p>Stan: <em>If people really wanted to add something like this, and get
it working for the first time, they ought to modify ser-unix.c to send
some kind of out-of-band message to a specially-setup stub and have the
switch happen &quot;in between&quot; packets, so that from remote protocol&rsquo;s point
of view, nothing actually happened.</em>
</p>
</dd>
<dt>&lsquo;<samp>B <var>addr</var>,<var>mode</var></samp>&rsquo;</dt>
<dd><a name="index-B-packet"></a>
<p>Set (<var>mode</var> is &lsquo;<samp>S</samp>&rsquo;) or clear (<var>mode</var> is &lsquo;<samp>C</samp>&rsquo;) a
breakpoint at <var>addr</var>.
</p>
<p>Don&rsquo;t use this packet.  Use the &lsquo;<samp>Z</samp>&rsquo; and &lsquo;<samp>z</samp>&rsquo; packets instead
(see <a href="#insert-breakpoint-or-watchpoint-packet">insert breakpoint or watchpoint packet</a>).
</p>
<a name="index-bc-packet"></a>
<a name="bc"></a></dd>
<dt>&lsquo;<samp>bc</samp>&rsquo;</dt>
<dd><p>Backward continue.  Execute the target system in reverse.  No parameter.
See <a href="Reverse-Execution.html#Reverse-Execution">Reverse Execution</a>, for more information.
</p>
<p>Reply:
See <a href="Stop-Reply-Packets.html#Stop-Reply-Packets">Stop Reply Packets</a>, for the reply specifications.
</p>
<a name="index-bs-packet"></a>
<a name="bs"></a></dd>
<dt>&lsquo;<samp>bs</samp>&rsquo;</dt>
<dd><p>Backward single step.  Execute one instruction in reverse.  No parameter.
See <a href="Reverse-Execution.html#Reverse-Execution">Reverse Execution</a>, for more information.
</p>
<p>Reply:
See <a href="Stop-Reply-Packets.html#Stop-Reply-Packets">Stop Reply Packets</a>, for the reply specifications.
</p>
</dd>
<dt>&lsquo;<samp>c <span class="roman">[</span><var>addr</var><span class="roman">]</span></samp>&rsquo;</dt>
<dd><a name="index-c-packet"></a>
<p>Continue at <var>addr</var>, which is the address to resume.  If <var>addr</var>
is omitted, resume at current address.
</p>
<p>This packet is deprecated for multi-threading support.  See <a href="#vCont-packet">vCont packet</a>.
</p>
<p>Reply:
See <a href="Stop-Reply-Packets.html#Stop-Reply-Packets">Stop Reply Packets</a>, for the reply specifications.
</p>
</dd>
<dt>&lsquo;<samp>C <var>sig</var><span class="roman">[</span>;<var>addr</var><span class="roman">]</span></samp>&rsquo;</dt>
<dd><a name="index-C-packet"></a>
<p>Continue with signal <var>sig</var> (hex signal number).  If
&lsquo;<samp>;<var>addr</var></samp>&rsquo; is omitted, resume at same address.
</p>
<p>This packet is deprecated for multi-threading support.  See <a href="#vCont-packet">vCont packet</a>.
</p>
<p>Reply:
See <a href="Stop-Reply-Packets.html#Stop-Reply-Packets">Stop Reply Packets</a>, for the reply specifications.
</p>
</dd>
<dt>&lsquo;<samp>d</samp>&rsquo;</dt>
<dd><a name="index-d-packet"></a>
<p>Toggle debug flag.
</p>
<p>Don&rsquo;t use this packet; instead, define a general set packet
(see <a href="General-Query-Packets.html#General-Query-Packets">General Query Packets</a>).
</p>
</dd>
<dt>&lsquo;<samp>D</samp>&rsquo;</dt>
<dt>&lsquo;<samp>D;<var>pid</var></samp>&rsquo;</dt>
<dd><a name="index-D-packet"></a>
<p>The first form of the packet is used to detach <small>GDB</small> from the 
remote system.  It is sent to the remote target
before <small>GDB</small> disconnects via the <code>detach</code> command.
</p>
<p>The second form, including a process ID, is used when multiprocess
protocol extensions are enabled (see <a href="General-Query-Packets.html#multiprocess-extensions">multiprocess extensions</a>), to
detach only a specific process.  The <var>pid</var> is specified as a
big-endian hex string.
</p>
<p>Reply:
</p><dl compact="compact">
<dt>&lsquo;<samp>OK</samp>&rsquo;</dt>
<dd><p>for success
</p></dd>
<dt>&lsquo;<samp>E <var>NN</var></samp>&rsquo;</dt>
<dd><p>for an error
</p></dd>
</dl>

</dd>
<dt>&lsquo;<samp>F <var>RC</var>,<var>EE</var>,<var>CF</var>;<var>XX</var></samp>&rsquo;</dt>
<dd><a name="index-F-packet"></a>
<p>A reply from <small>GDB</small> to an &lsquo;<samp>F</samp>&rsquo; packet sent by the target.
This is part of the File-I/O protocol extension.  See <a href="File_002dI_002fO-Remote-Protocol-Extension.html#File_002dI_002fO-Remote-Protocol-Extension">File-I/O Remote Protocol Extension</a>, for the specification.
</p>
</dd>
<dt>&lsquo;<samp>g</samp>&rsquo;</dt>
<dd><a name="read-registers-packet"></a><a name="index-g-packet"></a>
<p>Read general registers.
</p>
<p>Reply:
</p><dl compact="compact">
<dt>&lsquo;<samp><var>XX&hellip;</var></samp>&rsquo;</dt>
<dd><p>Each byte of register data is described by two hex digits.  The bytes
with the register are transmitted in target byte order.  The size of
each register and their position within the &lsquo;<samp>g</samp>&rsquo; packet are
determined by the <small>GDB</small> internal gdbarch functions
<code>DEPRECATED_REGISTER_RAW_SIZE</code> and <code>gdbarch_register_name</code>.  The
specification of several standard &lsquo;<samp>g</samp>&rsquo; packets is specified below.
</p>
<p>When reading registers from a trace frame (see <a href="Analyze-Collected-Data.html#Analyze-Collected-Data">Using the Collected Data</a>), the stub may also return a string of
literal &lsquo;<samp>x</samp>&rsquo;&rsquo;s in place of the register data digits, to indicate
that the corresponding register has not been collected, thus its value
is unavailable.  For example, for an architecture with 4 registers of
4 bytes each, the following reply indicates to <small>GDB</small> that
registers 0 and 2 have not been collected, while registers 1 and 3
have been collected, and both have zero value:
</p>
<div class="smallexample">
<pre class="smallexample">-&gt; <code>g</code>
&lt;- <code>xxxxxxxx00000000xxxxxxxx00000000</code>
</pre></div>

</dd>
<dt>&lsquo;<samp>E <var>NN</var></samp>&rsquo;</dt>
<dd><p>for an error.
</p></dd>
</dl>

</dd>
<dt>&lsquo;<samp>G <var>XX&hellip;</var></samp>&rsquo;</dt>
<dd><a name="index-G-packet"></a>
<p>Write general registers.  See <a href="#read-registers-packet">read registers packet</a>, for a
description of the <var>XX&hellip;</var> data.
</p>
<p>Reply:
</p><dl compact="compact">
<dt>&lsquo;<samp>OK</samp>&rsquo;</dt>
<dd><p>for success
</p></dd>
<dt>&lsquo;<samp>E <var>NN</var></samp>&rsquo;</dt>
<dd><p>for an error
</p></dd>
</dl>

</dd>
<dt>&lsquo;<samp>H <var>op</var> <var>thread-id</var></samp>&rsquo;</dt>
<dd><a name="index-H-packet"></a>
<p>Set thread for subsequent operations (&lsquo;<samp>m</samp>&rsquo;, &lsquo;<samp>M</samp>&rsquo;, &lsquo;<samp>g</samp>&rsquo;,
&lsquo;<samp>G</samp>&rsquo;, et.al.).  Depending on the operation to be performed, <var>op</var>
should be &lsquo;<samp>c</samp>&rsquo; for step and continue operations (note that this
is deprecated, supporting the &lsquo;<samp>vCont</samp>&rsquo; command is a better
option), and &lsquo;<samp>g</samp>&rsquo; for other operations.  The thread designator
<var>thread-id</var> has the format and interpretation described in
<a href="#thread_002did-syntax">thread-id syntax</a>.
</p>
<p>Reply:
</p><dl compact="compact">
<dt>&lsquo;<samp>OK</samp>&rsquo;</dt>
<dd><p>for success
</p></dd>
<dt>&lsquo;<samp>E <var>NN</var></samp>&rsquo;</dt>
<dd><p>for an error
</p></dd>
</dl>


</dd>
<dt>&lsquo;<samp>i <span class="roman">[</span><var>addr</var><span class="roman">[</span>,<var>nnn</var><span class="roman">]]</span></samp>&rsquo;</dt>
<dd><a name="cycle-step-packet"></a><a name="index-i-packet"></a>
<p>Step the remote target by a single clock cycle.  If &lsquo;<samp>,<var>nnn</var></samp>&rsquo; is
present, cycle step <var>nnn</var> cycles.  If <var>addr</var> is present, cycle
step starting at that address.
</p>
</dd>
<dt>&lsquo;<samp>I</samp>&rsquo;</dt>
<dd><a name="index-I-packet"></a>
<p>Signal, then cycle step.  See <a href="#step-with-signal-packet">step with signal packet</a>.  See <a href="#cycle-step-packet">cycle step packet</a>.
</p>
</dd>
<dt>&lsquo;<samp>k</samp>&rsquo;</dt>
<dd><a name="index-k-packet"></a>
<p>Kill request.
</p>
<p>The exact effect of this packet is not specified.
</p>
<p>For a bare-metal target, it may power cycle or reset the target
system.  For that reason, the &lsquo;<samp>k</samp>&rsquo; packet has no reply.
</p>
<p>For a single-process target, it may kill that process if possible.
</p>
<p>A multiple-process target may choose to kill just one process, or all
that are under <small>GDB</small>&rsquo;s control.  For more precise control, use
the vKill packet (see <a href="#vKill-packet">vKill packet</a>).
</p>
<p>If the target system immediately closes the connection in response to
&lsquo;<samp>k</samp>&rsquo;, <small>GDB</small> does not consider the lack of packet
acknowledgment to be an error, and assumes the kill was successful.
</p>
<p>If connected using <kbd>target extended-remote</kbd>, and the target does
not close the connection in response to a kill request, <small>GDB</small>
probes the target state as if a new connection was opened
(see <a href="#g_t_003f-packet">? packet</a>).
</p>
</dd>
<dt>&lsquo;<samp>m <var>addr</var>,<var>length</var></samp>&rsquo;</dt>
<dd><a name="index-m-packet"></a>
<p>Read <var>length</var> addressable memory units starting at address <var>addr</var>
(see <a href="Memory.html#addressable-memory-unit">addressable memory unit</a>).  Note that <var>addr</var> may not be aligned to
any particular boundary.
</p>
<p>The stub need not use any particular size or alignment when gathering
data from memory for the response; even if <var>addr</var> is word-aligned
and <var>length</var> is a multiple of the word size, the stub is free to
use byte accesses, or not.  For this reason, this packet may not be
suitable for accessing memory-mapped I/O devices.
<a name="index-alignment-of-remote-memory-accesses"></a>
<a name="index-size-of-remote-memory-accesses"></a>
<a name="index-memory_002c-alignment-and-size-of-remote-accesses"></a>
</p>
<p>Reply:
</p><dl compact="compact">
<dt>&lsquo;<samp><var>XX&hellip;</var></samp>&rsquo;</dt>
<dd><p>Memory contents; each byte is transmitted as a two-digit hexadecimal number.
The reply may contain fewer addressable memory units than requested if the
server was able to read only part of the region of memory.
</p></dd>
<dt>&lsquo;<samp>E <var>NN</var></samp>&rsquo;</dt>
<dd><p><var>NN</var> is errno
</p></dd>
</dl>

</dd>
<dt>&lsquo;<samp>M <var>addr</var>,<var>length</var>:<var>XX&hellip;</var></samp>&rsquo;</dt>
<dd><a name="index-M-packet"></a>
<p>Write <var>length</var> addressable memory units starting at address <var>addr</var>
(see <a href="Memory.html#addressable-memory-unit">addressable memory unit</a>).  The data is given by <var>XX&hellip;</var>; each
byte is transmitted as a two-digit hexadecimal number.
</p>
<p>Reply:
</p><dl compact="compact">
<dt>&lsquo;<samp>OK</samp>&rsquo;</dt>
<dd><p>for success
</p></dd>
<dt>&lsquo;<samp>E <var>NN</var></samp>&rsquo;</dt>
<dd><p>for an error (this includes the case where only part of the data was
written).
</p></dd>
</dl>

</dd>
<dt>&lsquo;<samp>p <var>n</var></samp>&rsquo;</dt>
<dd><a name="index-p-packet"></a>
<p>Read the value of register <var>n</var>; <var>n</var> is in hex.
See <a href="#read-registers-packet">read registers packet</a>, for a description of how the returned
register value is encoded.
</p>
<p>Reply:
</p><dl compact="compact">
<dt>&lsquo;<samp><var>XX&hellip;</var></samp>&rsquo;</dt>
<dd><p>the register&rsquo;s value
</p></dd>
<dt>&lsquo;<samp>E <var>NN</var></samp>&rsquo;</dt>
<dd><p>for an error
</p></dd>
<dt>&lsquo;<samp><!-- /@w --></samp>&rsquo;</dt>
<dd><p>Indicating an unrecognized <var>query</var>.
</p></dd>
</dl>

</dd>
<dt>&lsquo;<samp>P <var>n&hellip;</var>=<var>r&hellip;</var></samp>&rsquo;</dt>
<dd><a name="write-register-packet"></a><a name="index-P-packet"></a>
<p>Write register <var>n&hellip;</var> with value <var>r&hellip;</var>.  The register
number <var>n</var> is in hexadecimal, and <var>r&hellip;</var> contains two hex
digits for each byte in the register (target byte order).
</p>
<p>Reply:
</p><dl compact="compact">
<dt>&lsquo;<samp>OK</samp>&rsquo;</dt>
<dd><p>for success
</p></dd>
<dt>&lsquo;<samp>E <var>NN</var></samp>&rsquo;</dt>
<dd><p>for an error
</p></dd>
</dl>

</dd>
<dt>&lsquo;<samp>q <var>name</var> <var>params</var>&hellip;</samp>&rsquo;</dt>
<dt>&lsquo;<samp>Q <var>name</var> <var>params</var>&hellip;</samp>&rsquo;</dt>
<dd><a name="index-q-packet"></a>
<a name="index-Q-packet"></a>
<p>General query (&lsquo;<samp>q</samp>&rsquo;) and set (&lsquo;<samp>Q</samp>&rsquo;).  These packets are
described fully in <a href="General-Query-Packets.html#General-Query-Packets">General Query Packets</a>.
</p>
</dd>
<dt>&lsquo;<samp>r</samp>&rsquo;</dt>
<dd><a name="index-r-packet"></a>
<p>Reset the entire system.
</p>
<p>Don&rsquo;t use this packet; use the &lsquo;<samp>R</samp>&rsquo; packet instead.
</p>
</dd>
<dt>&lsquo;<samp>R <var>XX</var></samp>&rsquo;</dt>
<dd><a name="index-R-packet"></a>
<p>Restart the program being debugged.  The <var>XX</var>, while needed, is ignored.
This packet is only available in extended mode (see <a href="#extended-mode">extended mode</a>).
</p>
<p>The &lsquo;<samp>R</samp>&rsquo; packet has no reply.
</p>
</dd>
<dt>&lsquo;<samp>s <span class="roman">[</span><var>addr</var><span class="roman">]</span></samp>&rsquo;</dt>
<dd><a name="index-s-packet"></a>
<p>Single step, resuming at <var>addr</var>.  If
<var>addr</var> is omitted, resume at same address.
</p>
<p>This packet is deprecated for multi-threading support.  See <a href="#vCont-packet">vCont packet</a>.
</p>
<p>Reply:
See <a href="Stop-Reply-Packets.html#Stop-Reply-Packets">Stop Reply Packets</a>, for the reply specifications.
</p>
</dd>
<dt>&lsquo;<samp>S <var>sig</var><span class="roman">[</span>;<var>addr</var><span class="roman">]</span></samp>&rsquo;</dt>
<dd><a name="step-with-signal-packet"></a><a name="index-S-packet"></a>
<p>Step with signal.  This is analogous to the &lsquo;<samp>C</samp>&rsquo; packet, but
requests a single-step, rather than a normal resumption of execution.
</p>
<p>This packet is deprecated for multi-threading support.  See <a href="#vCont-packet">vCont packet</a>.
</p>
<p>Reply:
See <a href="Stop-Reply-Packets.html#Stop-Reply-Packets">Stop Reply Packets</a>, for the reply specifications.
</p>
</dd>
<dt>&lsquo;<samp>t <var>addr</var>:<var>PP</var>,<var>MM</var></samp>&rsquo;</dt>
<dd><a name="index-t-packet"></a>
<p>Search backwards starting at address <var>addr</var> for a match with pattern
<var>PP</var> and mask <var>MM</var>, both of which are are 4 byte long.
There must be at least 3 digits in <var>addr</var>.
</p>
</dd>
<dt>&lsquo;<samp>T <var>thread-id</var></samp>&rsquo;</dt>
<dd><a name="index-T-packet"></a>
<p>Find out if the thread <var>thread-id</var> is alive.  See <a href="#thread_002did-syntax">thread-id syntax</a>.
</p>
<p>Reply:
</p><dl compact="compact">
<dt>&lsquo;<samp>OK</samp>&rsquo;</dt>
<dd><p>thread is still alive
</p></dd>
<dt>&lsquo;<samp>E <var>NN</var></samp>&rsquo;</dt>
<dd><p>thread is dead
</p></dd>
</dl>

</dd>
<dt>&lsquo;<samp>v</samp>&rsquo;</dt>
<dd><p>Packets starting with &lsquo;<samp>v</samp>&rsquo; are identified by a multi-letter name,
up to the first &lsquo;<samp>;</samp>&rsquo; or &lsquo;<samp>?</samp>&rsquo; (or the end of the packet).
</p>
</dd>
<dt>&lsquo;<samp>vAttach;<var>pid</var></samp>&rsquo;</dt>
<dd><a name="index-vAttach-packet"></a>
<p>Attach to a new process with the specified process ID <var>pid</var>.
The process ID is a
hexadecimal integer identifying the process.  In all-stop mode, all
threads in the attached process are stopped; in non-stop mode, it may be
attached without being stopped if that is supported by the target.
</p>

<p>This packet is only available in extended mode (see <a href="#extended-mode">extended mode</a>).
</p>
<p>Reply:
</p><dl compact="compact">
<dt>&lsquo;<samp>E <var>nn</var></samp>&rsquo;</dt>
<dd><p>for an error
</p></dd>
<dt>&lsquo;<samp><span class="roman">Any stop packet</span></samp>&rsquo;</dt>
<dd><p>for success in all-stop mode (see <a href="Stop-Reply-Packets.html#Stop-Reply-Packets">Stop Reply Packets</a>)
</p></dd>
<dt>&lsquo;<samp>OK</samp>&rsquo;</dt>
<dd><p>for success in non-stop mode (see <a href="Remote-Non_002dStop.html#Remote-Non_002dStop">Remote Non-Stop</a>)
</p></dd>
</dl>

</dd>
<dt>&lsquo;<samp>vCont<span class="roman">[</span>;<var>action</var><span class="roman">[</span>:<var>thread-id</var><span class="roman">]]</span>&hellip;</samp>&rsquo;</dt>
<dd><a name="index-vCont-packet"></a>
<a name="vCont-packet"></a><p>Resume the inferior, specifying different actions for each thread.
If an action is specified with no <var>thread-id</var>, then it is applied to any
threads that don&rsquo;t have a specific action specified; if no default action is
specified then other threads should remain stopped in all-stop mode and
in their current state in non-stop mode.
Specifying multiple
default actions is an error; specifying no actions is also an error.
Thread IDs are specified using the syntax described in <a href="#thread_002did-syntax">thread-id syntax</a>.
</p>
<p>Currently supported actions are:
</p>
<dl compact="compact">
<dt>&lsquo;<samp>c</samp>&rsquo;</dt>
<dd><p>Continue.
</p></dd>
<dt>&lsquo;<samp>C <var>sig</var></samp>&rsquo;</dt>
<dd><p>Continue with signal <var>sig</var>.  The signal <var>sig</var> should be two hex digits.
</p></dd>
<dt>&lsquo;<samp>s</samp>&rsquo;</dt>
<dd><p>Step.
</p></dd>
<dt>&lsquo;<samp>S <var>sig</var></samp>&rsquo;</dt>
<dd><p>Step with signal <var>sig</var>.  The signal <var>sig</var> should be two hex digits.
</p></dd>
<dt>&lsquo;<samp>t</samp>&rsquo;</dt>
<dd><p>Stop.
</p></dd>
<dt>&lsquo;<samp>r <var>start</var>,<var>end</var></samp>&rsquo;</dt>
<dd><p>Step once, and then keep stepping as long as the thread stops at
addresses between <var>start</var> (inclusive) and <var>end</var> (exclusive).
The remote stub reports a stop reply when either the thread goes out
of the range or is stopped due to an unrelated reason, such as hitting
a breakpoint.  See <a href="Continuing-and-Stepping.html#range-stepping">range stepping</a>.
</p>
<p>If the range is empty (<var>start</var> == <var>end</var>), then the action
becomes equivalent to the &lsquo;<samp>s</samp>&rsquo; action.  In other words,
single-step once, and report the stop (even if the stepped instruction
jumps to <var>start</var>).
</p>
<p>(A stop reply may be sent at any point even if the PC is still within
the stepping range; for example, it is valid to implement this packet
in a degenerate way as a single instruction step operation.)
</p>
</dd>
</dl>

<p>The optional argument <var>addr</var> normally associated with the 
&lsquo;<samp>c</samp>&rsquo;, &lsquo;<samp>C</samp>&rsquo;, &lsquo;<samp>s</samp>&rsquo;, and &lsquo;<samp>S</samp>&rsquo; packets is
not supported in &lsquo;<samp>vCont</samp>&rsquo;.
</p>
<p>The &lsquo;<samp>t</samp>&rsquo; action is only relevant in non-stop mode
(see <a href="Remote-Non_002dStop.html#Remote-Non_002dStop">Remote Non-Stop</a>) and may be ignored by the stub otherwise.
A stop reply should be generated for any affected thread not already stopped.
When a thread is stopped by means of a &lsquo;<samp>t</samp>&rsquo; action,
the corresponding stop reply should indicate that the thread has stopped with
signal &lsquo;<samp>0</samp>&rsquo;, regardless of whether the target uses some other signal
as an implementation detail.
</p>
<p>The stub must support &lsquo;<samp>vCont</samp>&rsquo; if it reports support for
multiprocess extensions (see <a href="General-Query-Packets.html#multiprocess-extensions">multiprocess extensions</a>).  Note that in
this case &lsquo;<samp>vCont</samp>&rsquo; actions can be specified to apply to all threads
in a process by using the &lsquo;<samp>p<var>pid</var>.-1</samp>&rsquo; form of the
<var>thread-id</var>.
</p>
<p>Reply:
See <a href="Stop-Reply-Packets.html#Stop-Reply-Packets">Stop Reply Packets</a>, for the reply specifications.
</p>
</dd>
<dt>&lsquo;<samp>vCont?</samp>&rsquo;</dt>
<dd><a name="index-vCont_003f-packet"></a>
<p>Request a list of actions supported by the &lsquo;<samp>vCont</samp>&rsquo; packet.
</p>
<p>Reply:
</p><dl compact="compact">
<dt>&lsquo;<samp>vCont<span class="roman">[</span>;<var>action</var>&hellip;<span class="roman">]</span></samp>&rsquo;</dt>
<dd><p>The &lsquo;<samp>vCont</samp>&rsquo; packet is supported.  Each <var>action</var> is a supported
command in the &lsquo;<samp>vCont</samp>&rsquo; packet.
</p></dd>
<dt>&lsquo;<samp><!-- /@w --></samp>&rsquo;</dt>
<dd><p>The &lsquo;<samp>vCont</samp>&rsquo; packet is not supported.
</p></dd>
</dl>

<a name="vCtrlC-packet"></a></dd>
<dt>&lsquo;<samp>vCtrlC</samp>&rsquo;</dt>
<dd><a name="index-vCtrlC-packet"></a>
<p>Interrupt remote target as if a control-C was pressed on the remote
terminal.  This is the equivalent to reacting to the <code>^C</code>
(&lsquo;<samp>\003</samp>&rsquo;, the control-C character) character in all-stop mode
while the target is running, except this works in non-stop mode.
See <a href="Interrupts.html#interrupting-remote-targets">interrupting remote targets</a>, for more info on the all-stop
variant.
</p>
<p>Reply:
</p><dl compact="compact">
<dt>&lsquo;<samp>E <var>nn</var></samp>&rsquo;</dt>
<dd><p>for an error
</p></dd>
<dt>&lsquo;<samp>OK</samp>&rsquo;</dt>
<dd><p>for success
</p></dd>
</dl>

</dd>
<dt>&lsquo;<samp>vFile:<var>operation</var>:<var>parameter</var>&hellip;</samp>&rsquo;</dt>
<dd><a name="index-vFile-packet"></a>
<p>Perform a file operation on the target system.  For details,
see <a href="Host-I_002fO-Packets.html#Host-I_002fO-Packets">Host I/O Packets</a>.
</p>
</dd>
<dt>&lsquo;<samp>vFlashErase:<var>addr</var>,<var>length</var></samp>&rsquo;</dt>
<dd><a name="index-vFlashErase-packet"></a>
<p>Direct the stub to erase <var>length</var> bytes of flash starting at
<var>addr</var>.  The region may enclose any number of flash blocks, but
its start and end must fall on block boundaries, as indicated by the
flash block size appearing in the memory map (see <a href="Memory-Map-Format.html#Memory-Map-Format">Memory Map Format</a>).  <small>GDB</small> groups flash memory programming operations
together, and sends a &lsquo;<samp>vFlashDone</samp>&rsquo; request after each group; the
stub is allowed to delay erase operation until the &lsquo;<samp>vFlashDone</samp>&rsquo;
packet is received.
</p>
<p>Reply:
</p><dl compact="compact">
<dt>&lsquo;<samp>OK</samp>&rsquo;</dt>
<dd><p>for success
</p></dd>
<dt>&lsquo;<samp>E <var>NN</var></samp>&rsquo;</dt>
<dd><p>for an error
</p></dd>
</dl>

</dd>
<dt>&lsquo;<samp>vFlashWrite:<var>addr</var>:<var>XX&hellip;</var></samp>&rsquo;</dt>
<dd><a name="index-vFlashWrite-packet"></a>
<p>Direct the stub to write data to flash address <var>addr</var>.  The data
is passed in binary form using the same encoding as for the &lsquo;<samp>X</samp>&rsquo;
packet (see <a href="Overview.html#Binary-Data">Binary Data</a>).  The memory ranges specified by
&lsquo;<samp>vFlashWrite</samp>&rsquo; packets preceding a &lsquo;<samp>vFlashDone</samp>&rsquo; packet must
not overlap, and must appear in order of increasing addresses
(although &lsquo;<samp>vFlashErase</samp>&rsquo; packets for higher addresses may already
have been received; the ordering is guaranteed only between
&lsquo;<samp>vFlashWrite</samp>&rsquo; packets).  If a packet writes to an address that was
neither erased by a preceding &lsquo;<samp>vFlashErase</samp>&rsquo; packet nor by some other
target-specific method, the results are unpredictable.
</p>

<p>Reply:
</p><dl compact="compact">
<dt>&lsquo;<samp>OK</samp>&rsquo;</dt>
<dd><p>for success
</p></dd>
<dt>&lsquo;<samp>E.memtype</samp>&rsquo;</dt>
<dd><p>for vFlashWrite addressing non-flash memory
</p></dd>
<dt>&lsquo;<samp>E <var>NN</var></samp>&rsquo;</dt>
<dd><p>for an error
</p></dd>
</dl>

</dd>
<dt>&lsquo;<samp>vFlashDone</samp>&rsquo;</dt>
<dd><a name="index-vFlashDone-packet"></a>
<p>Indicate to the stub that flash programming operation is finished.
The stub is permitted to delay or batch the effects of a group of
&lsquo;<samp>vFlashErase</samp>&rsquo; and &lsquo;<samp>vFlashWrite</samp>&rsquo; packets until a
&lsquo;<samp>vFlashDone</samp>&rsquo; packet is received.  The contents of the affected
regions of flash memory are unpredictable until the &lsquo;<samp>vFlashDone</samp>&rsquo;
request is completed.
</p>
</dd>
<dt>&lsquo;<samp>vKill;<var>pid</var></samp>&rsquo;</dt>
<dd><a name="index-vKill-packet"></a>
<a name="vKill-packet"></a><p>Kill the process with the specified process ID <var>pid</var>, which is a
hexadecimal integer identifying the process.  This packet is used in
preference to &lsquo;<samp>k</samp>&rsquo; when multiprocess protocol extensions are
supported; see <a href="General-Query-Packets.html#multiprocess-extensions">multiprocess extensions</a>.
</p>
<p>Reply:
</p><dl compact="compact">
<dt>&lsquo;<samp>E <var>nn</var></samp>&rsquo;</dt>
<dd><p>for an error
</p></dd>
<dt>&lsquo;<samp>OK</samp>&rsquo;</dt>
<dd><p>for success
</p></dd>
</dl>

</dd>
<dt>&lsquo;<samp>vRun;<var>filename</var><span class="roman">[</span>;<var>argument</var><span class="roman">]</span>&hellip;</samp>&rsquo;</dt>
<dd><a name="index-vRun-packet"></a>
<p>Run the program <var>filename</var>, passing it each <var>argument</var> on its
command line.  The file and arguments are hex-encoded strings.  If
<var>filename</var> is an empty string, the stub may use a default program
(e.g. the last program run).  The program is created in the stopped
state.
</p>

<p>This packet is only available in extended mode (see <a href="#extended-mode">extended mode</a>).
</p>
<p>Reply:
</p><dl compact="compact">
<dt>&lsquo;<samp>E <var>nn</var></samp>&rsquo;</dt>
<dd><p>for an error
</p></dd>
<dt>&lsquo;<samp><span class="roman">Any stop packet</span></samp>&rsquo;</dt>
<dd><p>for success (see <a href="Stop-Reply-Packets.html#Stop-Reply-Packets">Stop Reply Packets</a>)
</p></dd>
</dl>

</dd>
<dt>&lsquo;<samp>vStopped</samp>&rsquo;</dt>
<dd><a name="index-vStopped-packet"></a>
<p>See <a href="Notification-Packets.html#Notification-Packets">Notification Packets</a>.
</p>
</dd>
<dt>&lsquo;<samp>X <var>addr</var>,<var>length</var>:<var>XX&hellip;</var></samp>&rsquo;</dt>
<dd><a name="X-packet"></a><a name="index-X-packet"></a>
<p>Write data to memory, where the data is transmitted in binary.
Memory is specified by its address <var>addr</var> and number of addressable memory
units <var>length</var> (see <a href="Memory.html#addressable-memory-unit">addressable memory unit</a>);
&lsquo;<samp><var>XX</var>&hellip;</samp>&rsquo; is binary data (see <a href="Overview.html#Binary-Data">Binary Data</a>).
</p>
<p>Reply:
</p><dl compact="compact">
<dt>&lsquo;<samp>OK</samp>&rsquo;</dt>
<dd><p>for success
</p></dd>
<dt>&lsquo;<samp>E <var>NN</var></samp>&rsquo;</dt>
<dd><p>for an error
</p></dd>
</dl>

</dd>
<dt>&lsquo;<samp>z <var>type</var>,<var>addr</var>,<var>kind</var></samp>&rsquo;</dt>
<dt>&lsquo;<samp>Z <var>type</var>,<var>addr</var>,<var>kind</var></samp>&rsquo;</dt>
<dd><a name="insert-breakpoint-or-watchpoint-packet"></a><a name="index-z-packet"></a>
<a name="index-Z-packets"></a>
<p>Insert (&lsquo;<samp>Z</samp>&rsquo;) or remove (&lsquo;<samp>z</samp>&rsquo;) a <var>type</var> breakpoint or
watchpoint starting at address <var>address</var> of kind <var>kind</var>.
</p>
<p>Each breakpoint and watchpoint packet <var>type</var> is documented
separately.
</p>
<p><em>Implementation notes: A remote target shall return an empty string
for an unrecognized breakpoint or watchpoint packet <var>type</var>.  A
remote target shall support either both or neither of a given
&lsquo;<samp>Z<var>type</var>&hellip;</samp>&rsquo; and &lsquo;<samp>z<var>type</var>&hellip;</samp>&rsquo; packet pair.  To
avoid potential problems with duplicate packets, the operations should
be implemented in an idempotent way.</em>
</p>
</dd>
<dt>&lsquo;<samp>z0,<var>addr</var>,<var>kind</var></samp>&rsquo;</dt>
<dt>&lsquo;<samp>Z0,<var>addr</var>,<var>kind</var><span class="roman">[</span>;<var>cond_list</var>&hellip;<span class="roman">]</span><span class="roman">[</span>;cmds:<var>persist</var>,<var>cmd_list</var>&hellip;<span class="roman">]</span></samp>&rsquo;</dt>
<dd><a name="index-z0-packet"></a>
<a name="index-Z0-packet"></a>
<p>Insert (&lsquo;<samp>Z0</samp>&rsquo;) or remove (&lsquo;<samp>z0</samp>&rsquo;) a memory breakpoint at address
<var>addr</var> of type <var>kind</var>.
</p>
<p>A memory breakpoint is implemented by replacing the instruction at
<var>addr</var> with a software breakpoint or trap instruction.  The
<var>kind</var> is target-specific and typically indicates the size of
the breakpoint in bytes that should be inserted.  E.g., the <small>ARM</small>
and <small>MIPS</small> can insert either a 2 or 4 byte breakpoint.  Some
architectures have additional meanings for <var>kind</var>;
<var>cond_list</var> is an optional list of conditional expressions in bytecode
form that should be evaluated on the target&rsquo;s side.  These are the
conditions that should be taken into consideration when deciding if
the breakpoint trigger should be reported back to <var>GDBN</var>.
</p>
<p>See also the &lsquo;<samp>swbreak</samp>&rsquo; stop reason (see <a href="Stop-Reply-Packets.html#swbreak-stop-reason">swbreak stop reason</a>)
for how to best report a memory breakpoint event to <small>GDB</small>.
</p>
<p>The <var>cond_list</var> parameter is comprised of a series of expressions,
concatenated without separators. Each expression has the following form:
</p>
<dl compact="compact">
<dt>&lsquo;<samp>X <var>len</var>,<var>expr</var></samp>&rsquo;</dt>
<dd><p><var>len</var> is the length of the bytecode expression and <var>expr</var> is the
actual conditional expression in bytecode form.
</p>
</dd>
</dl>

<p>The optional <var>cmd_list</var> parameter introduces commands that may be
run on the target, rather than being reported back to <small>GDB</small>.
The parameter starts with a numeric flag <var>persist</var>; if the flag is
nonzero, then the breakpoint may remain active and the commands
continue to be run even when <small>GDB</small> disconnects from the target.
Following this flag is a series of expressions concatenated with no
separators.  Each expression has the following form:
</p>
<dl compact="compact">
<dt>&lsquo;<samp>X <var>len</var>,<var>expr</var></samp>&rsquo;</dt>
<dd><p><var>len</var> is the length of the bytecode expression and <var>expr</var> is the
actual conditional expression in bytecode form.
</p>
</dd>
</dl>

<p>see <a href="Architecture_002dSpecific-Protocol-Details.html#Architecture_002dSpecific-Protocol-Details">Architecture-Specific Protocol Details</a>.
</p>
<p><em>Implementation note: It is possible for a target to copy or move
code that contains memory breakpoints (e.g., when implementing
overlays).  The behavior of this packet, in the presence of such a
target, is not defined.</em>
</p>
<p>Reply:
</p><dl compact="compact">
<dt>&lsquo;<samp>OK</samp>&rsquo;</dt>
<dd><p>success
</p></dd>
<dt>&lsquo;<samp><!-- /@w --></samp>&rsquo;</dt>
<dd><p>not supported
</p></dd>
<dt>&lsquo;<samp>E <var>NN</var></samp>&rsquo;</dt>
<dd><p>for an error
</p></dd>
</dl>

</dd>
<dt>&lsquo;<samp>z1,<var>addr</var>,<var>kind</var></samp>&rsquo;</dt>
<dt>&lsquo;<samp>Z1,<var>addr</var>,<var>kind</var><span class="roman">[</span>;<var>cond_list</var>&hellip;<span class="roman">]</span></samp>&rsquo;</dt>
<dd><a name="index-z1-packet"></a>
<a name="index-Z1-packet"></a>
<p>Insert (&lsquo;<samp>Z1</samp>&rsquo;) or remove (&lsquo;<samp>z1</samp>&rsquo;) a hardware breakpoint at
address <var>addr</var>.
</p>
<p>A hardware breakpoint is implemented using a mechanism that is not
dependant on being able to modify the target&rsquo;s memory.  The <var>kind</var>
and <var>cond_list</var> have the same meaning as in &lsquo;<samp>Z0</samp>&rsquo; packets.
</p>
<p><em>Implementation note: A hardware breakpoint is not affected by code
movement.</em>
</p>
<p>Reply:
</p><dl compact="compact">
<dt>&lsquo;<samp>OK</samp>&rsquo;</dt>
<dd><p>success
</p></dd>
<dt>&lsquo;<samp><!-- /@w --></samp>&rsquo;</dt>
<dd><p>not supported
</p></dd>
<dt>&lsquo;<samp>E <var>NN</var></samp>&rsquo;</dt>
<dd><p>for an error
</p></dd>
</dl>

</dd>
<dt>&lsquo;<samp>z2,<var>addr</var>,<var>kind</var></samp>&rsquo;</dt>
<dt>&lsquo;<samp>Z2,<var>addr</var>,<var>kind</var></samp>&rsquo;</dt>
<dd><a name="index-z2-packet"></a>
<a name="index-Z2-packet"></a>
<p>Insert (&lsquo;<samp>Z2</samp>&rsquo;) or remove (&lsquo;<samp>z2</samp>&rsquo;) a write watchpoint at <var>addr</var>.
The number of bytes to watch is specified by <var>kind</var>.
</p>
<p>Reply:
</p><dl compact="compact">
<dt>&lsquo;<samp>OK</samp>&rsquo;</dt>
<dd><p>success
</p></dd>
<dt>&lsquo;<samp><!-- /@w --></samp>&rsquo;</dt>
<dd><p>not supported
</p></dd>
<dt>&lsquo;<samp>E <var>NN</var></samp>&rsquo;</dt>
<dd><p>for an error
</p></dd>
</dl>

</dd>
<dt>&lsquo;<samp>z3,<var>addr</var>,<var>kind</var></samp>&rsquo;</dt>
<dt>&lsquo;<samp>Z3,<var>addr</var>,<var>kind</var></samp>&rsquo;</dt>
<dd><a name="index-z3-packet"></a>
<a name="index-Z3-packet"></a>
<p>Insert (&lsquo;<samp>Z3</samp>&rsquo;) or remove (&lsquo;<samp>z3</samp>&rsquo;) a read watchpoint at <var>addr</var>.
The number of bytes to watch is specified by <var>kind</var>.
</p>
<p>Reply:
</p><dl compact="compact">
<dt>&lsquo;<samp>OK</samp>&rsquo;</dt>
<dd><p>success
</p></dd>
<dt>&lsquo;<samp><!-- /@w --></samp>&rsquo;</dt>
<dd><p>not supported
</p></dd>
<dt>&lsquo;<samp>E <var>NN</var></samp>&rsquo;</dt>
<dd><p>for an error
</p></dd>
</dl>

</dd>
<dt>&lsquo;<samp>z4,<var>addr</var>,<var>kind</var></samp>&rsquo;</dt>
<dt>&lsquo;<samp>Z4,<var>addr</var>,<var>kind</var></samp>&rsquo;</dt>
<dd><a name="index-z4-packet"></a>
<a name="index-Z4-packet"></a>
<p>Insert (&lsquo;<samp>Z4</samp>&rsquo;) or remove (&lsquo;<samp>z4</samp>&rsquo;) an access watchpoint at <var>addr</var>.
The number of bytes to watch is specified by <var>kind</var>.
</p>
<p>Reply:
</p><dl compact="compact">
<dt>&lsquo;<samp>OK</samp>&rsquo;</dt>
<dd><p>success
</p></dd>
<dt>&lsquo;<samp><!-- /@w --></samp>&rsquo;</dt>
<dd><p>not supported
</p></dd>
<dt>&lsquo;<samp>E <var>NN</var></samp>&rsquo;</dt>
<dd><p>for an error
</p></dd>
</dl>

</dd>
</dl>

<hr>
<div class="header">
<p>
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